<scp>β‐Mannanase</scp> production by <i>Penicillium citrinum</i> through <scp>solid‐state</scp> fermentation using açaí residual biomass (<scp><i>Euterpe oleracea</i></scp>)

Abstract

Abstract BACKGROUND Açaí core ( Euterpe oleracea ) is a residual biomass with high mannan content; thus it can become a good inducer for mannanase production by solid‐state fermentation (SSF). β‐Mannanase production from Penicillium citrinum was investigated using açaí seed as inducer and carbon source through SSF, as well as the properties of β‐mannanase in the crude extract. RESULTS In this study, a two‐stage screening was performed. The P. citrinum strain exhibited high specific enzymatic activity (29 ± 0.2 U mg −1 protein). Nitrogen addition was necessary to improve β‐mannanase activity (an increase of 389% with sodium nitrate). The effect of pH and temperature on β‐mannanase activity in the crude extract was evaluated, with the highest activity found at pH 4.6 and a temperature of 40–60 °C. The enzymes exhibited good thermal stability with 5 h of incubation at 40, 50 and 60 °C, retaining 90%, 55% and 60% of the initial activity, respectively. Furthermore, P. citrinum β‐mannanase exhibited high specificity against ivory nut mannan (234% relative activity), good activity in the presence of a range of metal ions and the ability to hydrolyze locust bean gum, producing mannose and mannooligosaccharides. CONCLUSION Based on such data, açaí seed can be used as an inducer of β‐mannanase. The P. citrinum crude enzymatic extract, rich in β‐mannanase, has potential industrial applications, especially in the food and feed industries.